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Ashok Mannolu Arunachalam, How toArraysJSES6

How to remove array duplicates in JavaScript

The Set collection

Since ES6, Set collection has been introduced which is really good and makes our life simple. Set is a collection which will not keep duplicates. It can also take any iterable objects as constructor arguments. In our case, it is an array with duplicated values.

const duplicates = [1, 2, 3, 3, 2, 1]
const unique = [ Set(duplicates)]
console.log(unique) // [ 1, 2, 3 ]

Array.filter function

It is better to know more options, in case of not-so-friendly environment. For instance, Set collection is supported by all the major browsers but few old-schools. Yes, I am looking at you IE! O_o

const duplicates = [1, 2, 3, 3, 2, 1];
const unique = duplicates.filter(
(item, index) => duplicates.indexOf(item) === index
console.log(unique); // [ 1, 2, 3 ]

Please prefer the Set option just for the simple of it!

We can do the same .indexOf trick using .map, .foreach as well. But, .filter is more readable among those! ^_^